Sound muffling sleep mask



FIG. 1 is a front view of a sound muffling sleep mask showing my newdesign;

FIG. 2 is a left side view thereof; and,

FIG. 3 is a back view thereof.

The broken lines shown in FIGS. 1-3 are for illustrative purposes onlyand forms no part of the claimed design.

The ornamental design for an sound muffling sleep mask, as shown.